docs(agents): add comment-style guidance and symlink CLAUDE.md to AGENTS.md

Co-Authored-By: mantra <mantra@stack-auth.com>

AGENTS.md

@@ -119,6 +119,7 @@ To see all development ports, refer to the index.html of `apps/dev-launchpad/pub
 - When adding code to the `private` part of the backend, put the actual implementation into `implementation` (if the submodule is checked out), and implement a simple fallback in `implementation-fallback` for self-hosters. `implementation.generated.ts` will automatically be generated, which you can then import from `index.ts`. (See the existing code as an example.) If the submodule isn't checked out, but you need to add code to the `private` part of the backend, let the user know.
 - Security-sensitive code on the backend that shouldn't be public should be in the `private` part of the backend.
 - When you fix some obscure bug, or otherwise make a small change that is the result of a complex thought, add a concise comment explaining the thought in detail. Your mental model should be that we want to keep track of all the tiny decisions that are not clearly visible in the code, such that when/if we rewrite the code in the future, we don't have to re-learn all the tiny decisions that were made iteratively.
+- Write comments as if the reader is new to the codebase but already familiar with the goal of the project. Don't explain what the project is trying to achieve; instead, explain the local context they'd be missing — why this particular piece of code exists, the non-obvious decisions behind it, and how it fits into the surrounding code.
 - If you create any temporary files, always suffix them with `.untracked` or `.untracked.<ext>` so they don't get committed to Git.
 - Super important: WE ARE AN OPEN-SOURCE PROJECT. NEVER PUT ANYTHING POTENTIALLY PRIVATE, SECURITY-SENSITIVE, OR CONFIDENTIAL INTO THE CODEBASE OR ANY PULL REQUEST DESCRIPTIONS. Don't mention customer data, security details, or other potentially sensitive information in comments, pull request descriptions, commit messages, or anywhere else.
 

CLAUDE.md

@@ -1,5 +0,0 @@
-# Hexclave
-
-## Commands
-- **Lint**: `pnpm lint`
-- **Typecheck**: `pnpm typecheck`

CLAUDE.md

@@ -0,0 +1 @@
+AGENTS.md